Transfer of cadmium and barium from soil to crops grown in tropical soils

Leônidas Carrijo Azevedo Melo,Luís Reynaldo Ferracciú Alleoni,Evandro Barbosa Da Silva

doi:10.1590/s0100-06832014000600028

Leônidas Carrijo Azevedo Melo, Luís Reynaldo Ferracciú Alleoni + Show 1 more

Open Access

https://doi.org/10.1590/s0100-06832014000600028

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Abstract

Phytotoxicity and transfer of potentially toxic elements, such as cadmium (Cd) or barium (Ba), depend on the availability of these elements in soils and on the plant species exposed to them. With this study, we aimed to evaluate the effect of Cd and Ba application rates on yields of pea (Pisum sativum L.), sorghum (Sorghum bicolor L.), soybean (Glycine max L.), and maize (Zea mays L.) grown under greenhouse conditions in an Oxisol and an Entisol with contrasting physical and chemical properties, and to correlate the amount taken up by plants with extractants commonly used in routine soil analysis, along with transfer coefficients (Bioconcentration Factor and Transfer Factor) in different parts of the plants. Plants were harvested at flowering stage and measured for yield and Cd or Ba concentrations in leaves, stems, and roots. The amount of Cd accumulated in the plants was satisfactorily evaluated by both DTPA and Mehlich-3 (M-3). Mehlich-3 did not relate to Ba accumulated in plants, suggesting it should not be used to predict Ba availability. The transfer coefficients were specific to soils and plants and are therefore not recommended for direct use in risk assessment models without taking soil properties and group of plants into account.

Highlights

Human activities have been increasing environmental pollution for decades
Areas contaminated with potentially toxic elements have steadily grown around the world, especially in developing countries (Li et al, 2009)
Cadmium (Cd) is of special concern among metals because it can be mobile in soils, toxic to plants and animals at very low concentrations (Das et al, 1997), and taken up by plants

Summary

Introduction

Human activities have been increasing environmental pollution for decades. Soils and water are two natural resources severely affected by these activities. Areas contaminated with potentially toxic elements have steadily grown around the world, especially in developing countries (Li et al, 2009) In this context, research on phytotoxicity and the transfer of metals to soils and plants provides useful information on metal bioaccumulation in crops and helps define limits for contaminants in soils. Cadmium (Cd) is of special concern among metals because it can be mobile in soils, toxic to plants and animals at very low concentrations (Das et al, 1997), and taken up by plants. These qualities are heightened in acidic soils because soil pH is indirectly correlated with Cd solubility and with its availability for uptake (McBride et al, 1997). In a recent study, Guerra et al (2012) found that Cd did not exceed the critical limit (1.0 mg kg-1, fresh weight) for human consumption in a set of vegetables samples collected at a distribution center in the city of São Paulo, Brazil

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